With the advent of the computer there has been a need for storing vast amounts of data. Several devices have been used to accomplish this task. One of these devices is a hard disk drive. A hard disk drive includes one or more disks mounted on a spindle for rotation. Data is typically stored in concentric tracks which are like rings on a tree. A transducer is passed over the surface of the disk or disks and data is read from the surface of the disk or written to the surface of the disks. Hard disk drives are used in all types of computers ranging from the largest supercomputer to many of the personal computers used in homes and offices throughout the world.
The disks within a hard disk drive are permanently mounted to the spindle. In addition, the environment within the housing of a disk drive is carefully controlled to prevent contaminants since particles the size of smoke from a cigarette can "trip" the transducer and cause it to contact the disk which results in a disk crash or undesirable loss of data. As a result, the individual disks from a disk drive are not replaced by the user of the computer. Since physical access to the hard disk drive is typically not needed most computers are physically configured so that the hard disk drive is placed within the computer where it is not seen by the user. In most computers the hard disk drive is attached to the data bus within the computer and is not removed until the hard disk drive is replaced.
Of course, there are always exceptions to such common configurations. In some instances, where particularly sensitive information is being stored on a hard disk drive, computer user's prefer to have an entire hard disk drive they can remove from the computer and lock within a safe when not being used. This prevents computer hackers from breaking codes and accessing the information on the hard disk drive since there is no way for a hacker to electronically access the information on the hard disk drive.
In the past, there have been removable hard disk drives and removable cartridges of hard disks. Disk cartridges, in which only the disks are removable, have shortcomings. U.S. Pat. No. 4,717,981 issued to Nigam et al. shows such a disk cartridge which has an automatically activated door. U.S. Pat. No. 4,870,518 shows the bay into which the cartridge from U.S. Pat. No. 4,717,981 is inserted. The disk cartridges are more susceptible to contamination since the cartridge is inserted into a port in the computer. The contaminated air must be cleaned by filtration or otherwise before the access door to the disk drive can be opened and the actuator arm which carries the read and write transducer heads can be inserted for reading and writing. Another shortcoming is that cartridge must be precisely aligned mechanically each time the cartridge is inserted into the bay to prevent misreads and so that the disk spins on a level plane. Mechanical alignment using clutching mechanisms and centering mechanisms is not as precise as a fixed hard disk drive in which mechanical alignment is permanently set at manufacture. Such alignment is becoming more critical as the track density on the disk drives increases. Currently, track densities of over 1000 tracks per inch are being used. At some point, the track densities in a cartridge will be unable to keep up with the track densities in a hard disk drive.
The removable hard disk drives of the past have also had shortcomings. Most of the removable hard disk drives have made electrical contact with the computer system using the pins or connectors on the disk drive. U.S. Pat. No. 5,010,426 issued to Krenz is an example of such a drive. The pins associated with connector 30 are engaged with the openings in connector 28. In U.S. Pat. No. 4,633,350 issued to Hanson, the pins 37 are moved into a mating connector by the camming motion after the disk drive is rotated into position. U.S. Pat. No. 4,833,554 issued to Dalziel et al. shows yet another example of pins aligned and slid into engagement with a mating connector. In the Dalziel et al. patent a pair of alignment pins are used. Among the shortcomings associated with each of these methods is the fact that the means for making the connection has a very limited life. For example, the number of cycles that such connections have would at best be approximately 500 cycles. In other words, in an environment where a user would be removing the drive on a daily basis, these drives would last around two years and then would "fail". The "failure" would actually be a failure of the connectors rather than a failing of the hard disk drive itself. Another shortcoming is that these removable disk drives are not easy to remove. The disk drive must be gripped and pulled to break the electrical contacts unlike a floppy disk which is ejected a short distance so that the operator can easily grip the floppy.
U.S. Pat. No. 4,893,210 issued to Mintzlaff is a hard disk drive assembly which can be attached and removed from a power supply to form a stand alone unit external to a computer. The Mintzlaff patent uses a zero insertion force type connector that acts or impinges directly onto the pins of the hard disk drive which carry the inputs to and outputs from the disk drive. The pins would be very susceptible to damage with this arrangement since the elements 42a and 42b which contact the pins of the hard disk drive must be nearly perfect aligned to prevent side loading. Even if the elements 42a and 42b are perfectly aligned, some bending of the pins of the hard disk drive is likely to occur since the pins in the hard disk drives generally stand unsupported. Elements 42a and 42b act outwardly and there is no support behind the pins. Thus, the Mintzlaff patent suffers from the same shortcomings with respect to the number of times the disk drive could be removed and attached as do the patents mentioned above. In addition, the Mintzlaff reference is a stand alone unit which does not have to fit within an opening in a computer. A computer case would have to be modified in order to accommodate a crank such as 15 in the Mintzlaff patent.
The arrangements for making electrical connections in the above references appear to be for making the insertion of the disk drives easier and more reliable rather on the first or subsequent times when a hard disk drive required field service. The above arrangements do not appear to be adapted for removal and insertion on a frequent basis, such as one or more times daily.
Yet another problem associated with current removable disk drives is the repeated forces placed on the hard disk drive unit. The hard disk drive units are able to absorb some shocks however they are still somewhat sensitive. If too much force or a force is repeatedly placed on a hard disk drive distortion may result in the housing and result in tracking errors and possible errors in recovering data.
Therefore, a hard disk drive capable of being removed daily or even a number of times per day is needed. Furthermore, a hard disk drive that can be removed easily would be advantageous. This requires an electrical connector which can be used over and over and which has a high duty cycle and an ejection mechanism. In addition, a removable hard disk drive which does not have alignment problems and reads and writes reliably is also needed. Further, a removable hard disk drive that can be inserted and removed from the computer with little or no force placed thereon is also desirable.